MBIO 2020 Lecture Notes - Lecture 9: Corepressor, Maltose, Groel
10 Nov 2016
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Document Summary
Protein folding - the physical process when a polypeptide folds into its characteristic 3d structure. Chaperons - proteins that assist the folding of proteins, prevents misfolding. Failure to fold properly - inactive or different/dangerous functions - prions: needed in crowded cytoplasm. Prokaryotes - folds after translation - needs chaperons. Eukaryotes - individual domains independently during translation - no chaperons. Bacterial chaperon systems - groel, groes, dnaj, dnak. Chaperon secb - helps proteins translocate across membrane - keeping it folded. About 10 splicing proteins - atpase, reca, dna pol. Proteins can sometimes remove their own intein. Intein - not needed for function, but prevents pre-mature folding. N end forms peptide bond with c-terminal. Circular molecule - very stable - plays a role in host defense - peptide antibiotics - pokes holes in sensitive cell membrane. Mrnas are short living - no waste: starts translation while transcription still going on, more than 1 ribosome can translate the same mrna.
